Horn: 57

57-HORN RELAY COIL OPEN/SHORT TO GROUND





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
Continuously.

- Set Condition:
When no voltage is detected on the Horn Relay Control circuit by the BCM.





Diagnostic Test

1. ERASE AND ATTEMPT TO RESET DTC
Turn the ignition on.
With the scan tool, erase the current Body Control Module DTC's.
Turn the ignition off, wait 10 seconds then turn the ignition on.
With the scan tool, read the current Body Control Module DTC's.
Attempt to operate the horn.
Does the scan tool display: HORN RELAY COIL OPEN/SHORT TO GROUND?

Yes

- Go To2

No

- The condition that caused this symptom is currently not present. Inspect the related wiring harness for a possible intermittent condition.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2. CHECK FUSE #19
Turn the ignition off.
Check fuse #19 in the PDC.
Is the fuse open?

Yes

- Replace the fuse. Check for a short to ground in the Horn Relay Output circuit from the PDC to the horns.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To3

3. INSTALL KNOWN GOOD RELAY
Turn the ignition off.
Remove the Horn Relay from the Power Distribution Center.
Substitute the original Horn Relay with a known good relay.
Turn the ignition on.
With the scan tool, erase the current Body Control Module DTCs.
Turn the engine off, wait 10 seconds then turn the ignition on.
Attempt to operate the horn.
With the scan tool, read the current Body Control Module DTC's.
Does the scan tool display: HORN RELAY COIL OPEN/SHORT TO GROUND?

Yes

- Go To4

No

- Replace the original Horn Relay.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4. (X4) HORN RELAY CONTROL CIRCUIT SHORT TO GROUND




Turn the ignition off.
Remove the Horn Relay from the Power Distribution Center.
Disconnect the Body Control Module C4 connector.
Measure the resistance of the (X4) Horn Relay Control circuit at the Horn Relay connector to ground.
Is the resistance below 5.0 ohms?

Yes

- Repair the (X4) Horn Relay Control circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To5

5. (X4) HORN RELAY CONTROL CIRCUIT OPEN




Turn the ignition off.
Remove the Horn Relay from the Power Distribution Center.
Disconnect the Body Control Module C4 connector.
Measure the resistance of the (X4) Horn Relay Control circuit between the BCM connector and the Horn Relay connector.
Is the resistance below 5.0 ohms?

Yes

- Replace the Body Control Module.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Repair the (X4) Horn Relay Control circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test